SumOfUs, the Washington, D.C.-based liberal group that pressured Apple (Nasdaq: AAPL), the world's most valuable technology company, about its Chinese contractors, is keeping the pressure on.

Via a new Web site, www.ethicaliphone.org, SumOfUs wants to keep the heat on the Cupertino, Calif.-based developer to improve labor practices for as many as a million workers in China. They are mainly employed by Taiwan's Hon Hai Precision Industries (Taipei: 2317).

In March, Apple CEO Timothy D. Cook visited two of the factories, which operate under the Foxconn name and pledged to deal with overtime and other issues. To date, we have been disappointed with Apple's progress, said Taren Stinebrickner-Kauffmann, SumOfUs executive director.

The new Web site was put up a year after two Foxconn workers making iPad2 products were killed. Apple shares fell $4.94 to $565.53, in Thursday afternoon trading.